Combustion method and furnace combustion chamber



Oct. 22, 1929. c. D. MONTAGUE COMBUSTION METHOD AND FURNACE COMBUSTION CHAMBER Filed June 25, 1925 ATTORNEY Patented Oct. 22, 1929 UNITED STATES PATENT OFFICE CHARLES D. MONTAGUE, oF NEW YORK, N. Y.

COMBUSTION METHOD ANI) FURNACE (IOItIBUSLIOlll CHAMBER Application led June 25, 1925. Serial No. 39,477.

formed of lire resistant material designed to constitute an insert to be positioned in the lire 1o pot of a furnace, such as a domestic heating furnace, of the types which are constructed or modified to burn a hydrocarbon fuel, usually discharged into the same by some form of spray ejector fuel nozzle type of burner.

In similar constructions now known it is a usual practice to direct the discharge from the burner nozzle either directly into the fire pot zone or directly against a metallic hot plate positioned in the fire pot to constitute 2o a hot target against which the fuel is directed.

Such constructions have not proved to be commercially satisfactory among other reasons due tothe fact that the combustion act 25 Was not completed prior to the contact of the burning gases against the water jacketed walls outlining the furnace. The-fact that soot and other carbon deposits are found in the outlet iiue and in contact with the water so jaclreted walls shows that with the known forms of such constructions some of the more difhcultly oxidizable hydrocarbon complexes in the fuel were not completely oxidized.

The primary object of the invention is to 35 provide for a complete, or at least a substantially complete, combustion of all of the hydrocarbon complexes present in the fuel under such conditions as will promote a rapid and complete oxidation before the hot prodto yucts of combustion are brought into the presence of the water jacketed and other walls containing the water, air or other heat extracting mediums usually employed in devices of this character.

lBroadly, this phase of the invention is attained by providing a long combustion chamber between the fuel discharging nozzle and the point or zone in the furnace where it is desired to abstract heat from the flaming .50 products of combustion.

' large volume of air necessary to burn the fuel.

.rent and the creation of noise which has ren- As it is of course impossible to provide a long, straight combustion zone within the narrow confines of the usual house furnace, the invention herein features a combustion chamber formed of telescopic tubes arranged to provide along tortuous passageway for the burning fuel and which arrangement incidentally provides for a mutual insulating from excessive heat losses of each inner conduit by the hot jacketing effect of its next adjacent outer conduit.

It is apparently required in order to insure a quick ignition of the more diliicultly vaporizable hydrocarbon complexes that a large amount of heat be concentrated on the fuel during the initial stages of the combustion act.

Accordingly, another object of the invention and featuring the tortuous passageway herein` disclosed, is to provide a baHle arranged to direct the heat backwardly on to the incoming unburned fuel so as to raise the temperature thereof rapidly and thereafter permit a relatively long timel duration for the subsequent stages ofthe combustion act; and 7 at all times maintain in the combustion zone conditions which will not tend to lower the temperature of the burning gases during their passage through the combustion zone.

In devices of this character heretofore used it has been usual to utilize all of the combustion supporting air for the purpose of spray ing the fuel and this necessitated the use of relatively large blowers for handling the This was objectionable in that it necessitated the use oflarge fans and correspondingly large motors for driving the same with the resulting heavy consumption of electric curdered such devices unpopular for domestic use. Further, it is believed that this manner of feeding all of the air through the burner deleteriously affected the combustion act in that the large volume of air present tended c5 to cool the hydrocarbons at the point where the highest temperature was desired.

Accordingly, another object of the invention is to provide for a sequential and grad ually increasing rate of feeding of the comloo bustion supporting air through the incoming end of the combustionchamber and t0 distribute the air at `spaced apart points adjacent this end in order to provide for a more perfect combustion than has been possible heretofore in this art.

Another object of the invention is to provide for economy in the original cost and in the cost of operation of the fan, motor, and other apparatus necessary to insure the vaporization, spraying or Avolatilization of the hydrocarbon discharged from the burner and incidentally to minimize the amount of air necessary to be handled by such apparatus.

Various other objects and advantages of the invention will be in part obvious from a consideration of the method features of the disclosure and from an inspection of the accompanying drawings, and in part will be more fully set forth in the following particu- 4lar description of one method of practicing the invention and in the inspection of'a furnace vembodying certain mechanical features of my invention, and the invention also consists in certain new and novel modifications of the preferred method and other features of construction and combination of parts hereinafter set forth and claimed.

In the accompanying drawings Figure 1 is a view in vertical axial cross section of the lower portion of a household heating furnace provided with an insert constituting a preferred embodiment of the invention. 4

Figure 2 is a horizontal sectional view taken on the broken line 2 2 of Figure 1 looking downwar ly.

. Figure 3 is an enlarged plan view of the air distributor and drip trough shown in reduced vertical section at the lower portion of Figure 1.

Figure 4 is a view in front end elevation of the air distributor shown in Figure 3; and

Figure 5 is a transverse sectional view taken on the line 5-5 of Figure 3.

In the following description and in the claims, parts will be identified by specific names for convenience of expression but they are intended to be as generic in their application to similar parts as the art will permit.

In the drawings there is shown a furnace including a water jacket shell 10 mounted on a concrete base 11 and provided with the usual coal supplying opening 12 and with the usual ash pit opening at 13. The shell10 encloses pockets 14 containing water, steam, air or other heat abstracting medium usual in furnaces of the type now in general use for heating household and industrial buildmgs.

The present disclosure is intended to illustrate the application of the invention to the household type o-f furnace and the combustion forming chamber' herein featured is formed as a separate insert designed to be pit opening when the usual door therefor is y removed. The front of the leg 16 is closed by means of a front plate 18 provided centrally thereof with an opening 19 closed by a cover plate 20. Through the plate extends a burner 21 preferably of the adjustable spray nozzle type and which burner is supplied with hydrocarbon fuel, such as crude oil, through the fuel intake pipe 22 and with air under pressure 'admitted through an air supplying pipe 23, as is usual in constructions of this character, except that the whole assembly is smaller than is usual wit-h this size furnace.

The present disclosure features a distinction over similar devices now known in that while the air supplied through the burner nozzle is under sufficient pressure and is present in sufficient volumetric amounts necessary to insure an effective spraying of the liquid fuel particles into the conduit, it is not intended that the air supplied through the nozzle be in sufficient amounts to supply the requisite alnount of oxygen necessary to insure lcomplete combustion of the hydrocarbon complexes present.

In order to supply the necessary amount of air an auxiliary air supply supplements the air supplied by the "burner but this supplemental air is not necessarily under pressure but is supplied by the natural draught created during the operation of the device disclosed. For this purpose the bottom of the leg 16 of the conduit is outlined by an air distributor 24. This air distributor, as particularly noted from Figures 3, 4 and 5, comprises essentially a metal foundation piece providing a support for a row of fire brick forming the major portion of the bottom of thecombustion chamber. 'lhe metal foundation includes a wide spreading V-shaped metal shelf 25 provided in the instant case with two parallel lines of air con-duits 26 in the form of short open end tubes projecting above the V-shaped shelf. Opposite edges of the metal shelf are supported from the bottom of the ash pit on L-shaped uprights 27, the horizontally extending flanges`28 of which are designed to fit between the vertical walls outlining the ash pit and the vertically depending fianges 29 of which constitute feet for supporting the shelf above the bottom of the ash pit and thus provide an air'passage'- Cil way 30 between the metal shelf and theb-otvtom of the ash pit. Positioned on top of the metal shelf is a series of flat fire bricks 31,` one for each transversely positioned pair of air conduits 26, positioned over the same as indi-v cated in dotted outlinesin Figures 3, 4 and 5,

longitudinally spaced apart to provide air Vents 32 for supplying combustion support-' bustion chamber at spaced apart points therein. The shelf 26 also acts as a drip pan for receiving any liquid particles which may fall from the combustion chamber and such dripv may be discharged through a drip opening 33 in the front wall 34 defining the front end of the air distributor.

Encircling the upper portion of the conduit arm 17 is a second cylindrical shaped conduit *35" which extends above the top of the conduit 17 and is closed by means of a closure plate 36. The closure 36 is in the form of a heavy thick plate of fire resistant4 material and will be referred to specifically as Fa baffle for reflecting heat downwardly through the combustion chamber 15 towards the incoming air discharged upwardly through the conm duits 32.

The conduit 35 rests on spaced apart risers 37 arranged to provide a plurality of circum- -ferentially spaced flaming fuel discharging conduits 38 therebetween as shown in Figure 2. The conduit 35 is of less diameter than the internal diameter of the shell 10 so as to provide an annular discharging passageway 39 between the second conduit and the outlining furnace metal shell 10.

It is appreciated that this construction forms an extremely long, tortuous passageway and the object of the construction is to y provide a length of combustion chamber between the burner and the point of Idischarge of the hot gases against the water jacketed walls which will be relatively long. This length must of course vary with different sizes and conditions of furnaces and isherein identified in certain of the claims as having a length materially greater than any other dimension but it is the intent to provide such length of passageway as will effect a sufficient time lapse to insure complete combustion of all of the hydrocarbon particles before the burned gas is brought in contact with the cooling eii'ect of the water jacketedshell.

It is assumed that the lighter more volatile hydrocarbon complexes are promptly burned closely following .the discharge of the same from the burning nozzle and that these burning gases will tend to heat the more 'difiicultly volatilizable hydrocarbon complexes at points farther on in the combustion chamber at which points the fresh supply of air is admitted through the auxiliary air supplying vents. The hot gases striking the'baflle appears to slow down what might otherwise be the normal rate of travel of the burning gases and there results an intensely heated but quiet burning of the fuel.

By means of a device such as is herein disclosed it has been found possible to utilize all or substantially all of the crude oil used with an unusually high efficiency and the producing of a temperature in the combustion chamber higher than has been found practical heretofore in devices of this character. Little or no soot is formed in the fuel passageways and every eort is made to minimize any cooling of the burning gases up to its point of engagement with the shell outlining the furnace.

The device disclosed also features economy l in the size of air blower heretofore regarded as necessary in such constructions with a resultant reduction in amount of electric energy necessary to driving such blower.

While I have shown and described, and have pointed out in the annexed claims, certain novel features ofjmyl invention, it will be understood that various omissions, substitutions and changes in the form and details of the device illustrated and l in its operation may be made by those skilled in the art without departing from the spirit of the invention.V

Having thus described my invention, I claim:--

1. 'In a household heating furnace, the combination of means forming a long tortuous combustion chamber, a hydrocarbon burner discharging fuel and a limited amount of air into one end of said long chamber, means intermediate the ends of said chamber for supplying combustion supporting air, means at the opposite end of said chamber "and in spaced relation to said burner and air supplying means for abstracting the heat of combustion from the burning fuel discharged from the combustion chamber `being formed of a heat refractoryrnaterial to minimize heat losses therethrough, saidchamber having a length materially greaterthan either of its other two dimensions-and having a length suiiicient to cause the hydrocarbons discharged into the same by the burner to be completely burned before subjected to the cooling eect of said heat abstraoting means.

2. In a furnace having a water jacket shell, a plurality of telescopic tubes of fire resistant material coacting to provide-a tortuous passageway including two parallel vertically extending passageways constituting a long conibustion chamber, a burner discharging into the innermost tube, and the outermost tube discharging against the inner wall of said water jacket shell.

3. In a household heating furnace, the combination of an L-shaped conduit, a burner discharging into one leg of said conduit, a tubular shell of fire resistant material having 1ts upper end closed and its lower end open andtelescopin the other leg of said L-shaped conduit and orming therewith a tortuous passageway constituting a combustion chami ber and a furnace including a Water jacketed shell enclosing said last named conduit and adapted to receive the heat of combustion discharged therefrom.

' 4. An insert for a furnace, said insert formed of heat resistant material, comprising a horizontally extending combustion chamber discharging at one end into an upstanding conduit, open at its upper end and adapted to receive flaming fuel from the combustion chamber at its lower end, a second conduit insulated from the combustion chamber, surrounding and spaced from the upper end of the first named conduit and extending above the same, a baille plate of fire resistant material constituting a closure for the top of the second conduit, and means for supporting the lower portion of the second conduit and coacting to provide ports for discharging the hot products of combustion from the bottom of the second conduit.

5. In a household heating furnace, the combination with an outer, metallic water jacketed shell, a combustion chamber con-` tained Within said shell and comprising a tubular insert of lire resistant material providing. a tortuous passageway with its discharge end adjacent the bottom of the inner side of said water jacketed shell, and with its intake end positioned below said shell, and said combustion chamber outlined up to its discharge end by the fire resistant material of said tubular insert, and a burner discharging into said intake end.

6. In a furnace, the combination of means discharged from the combustion chamber,

said chamber having a length materially greater than either of its other two dimensions and having a length sufficient to cause the hydrocarbons discharged into the same by the burner to be completely burned before subjected to the cooling elfect of said heat abstracting means, a plurality of air vents positioned adjacent the burner end of said chamber and spaced along the length thereof for supplying combustion supporting air to said chamber at a plurality of points and a portion of said chamber forming means between said air vents and said abstracting means being vertically disposed and subjected on opposite sides thereof directly to the heat of combustion in said chamber from the burning gases passing along said sides.

7. In a furnace, the combination of an L-shaped conduit, a burner discharging into one leg of said conduit, a closed end conduit telescoping the other leg of said L-shaped conduit and forming therewith a tortuous passageway constituting a combustion chamber, a shell enclosing said last named conduit and adapted to receive the heat of con'lbustion discharged therefrom, and means for supplying combustion supporting air at a plurality of points through the bottom side 0f the first named leg of the L-shaped conduit.

8. VAn insert for a furnace, said insert formed of heat resistant material, comprising an upstanding conduit, open at its upper end and adapted to receive flaming fuel at its lower end, a second conduit supported at its lower end surrounding and spaced from the upper end of thefirst nalned conduit and extending above the same, a closure for the top of the second conduit supported thereon, means at the lower portion of the second conduit constituting a plurality of circumferentially spaced apart ports for discharging hot products of combustion from the bottom of the second conduit, and means for discharging burning gases into the lower end of the upstanding conduit.

9. In a device of the class described, an air distributor constituting the bottoln of a combustion chamber and comprising a metal shelf perforated to form air conduits, uprights supporting the shelf to provide an air passageway beneath the shelf and open at one end, and fire bricks spaced apart on the top of the distributor and positioned above the shelf to permit the passage therebetween of air drawn through the air conduits in the metal shelf. i

10. In the art of burning a complex hydrocarbon fuel, the method which consists in discharging into the combustion zone and under pressure al stream of fuel particles with air in a volumetric amount insulicient to support the combustion of the hydrocarbons present and causing said pressure stream by its suction effect to draw into said fuel stream a plurality of air streams spaced apart longitudinally of the path of travel of the burning fuel while insulating said Zone to minimize heat losses and reduction in temperature of the burning gases, causing said streams to move under natural draft and in volumetric capacity capable of supplying an amount of air sufficient to insure complete combustion of all of the combustible complexes present, causing all of said air streams to enter the fuel stream adjacent the intake end of the combustion zone and in spaced relation to its discharge endl while subjecting the burning gases in the upper part of said combustion zone to heat reflected downwardly towards the incoming natural draft air streams, and maintaining said heat at a temperature greater than the combustion point of the burning gases.

l1. In the art of burning a complex hydrocarbon fuel, the method which consists in spraying into the lower intake end of a long combustion zone a stream of liquid fuel particles with air under pressure and in a volumetric amount insufiicient to support the combustion of the hydrocarbons present and drawing into said fuel stream a plurality of air streams not under pressure but spaced apart longitudinally and horizontally of the path of travel of the burning fuel, causing said streams to coact in supplying an amount of air sufficient to insure complete combustion of all of the combustible complexes present, causing all of said air streams to enter the fuel stream adjacent the intake end of the combustion zone and in spaced relation to its discharge end, subjecting said fuel and air streams at a point intermediate the ends of the combustion Zone and adjacent its lower intake end to the heat reflected back and from a subsequent stage of the combustion act to cause a rise in temperature of the cold air and incoming liquid fuel and thus cause the same to be heated to a point higher than the combustion point of the Vfuel before the flaming fuel reaches the upper portion of the combustion zone.

12. In a household heating furnace, the combination of means forming a long, tortuous combustion space outlined by refractory material, said means including an upstanding tubular wall and atop of refractory material constituting a baffle facing the intake end of the combustion space and adapted to be heated to incandescence by the burning gases passing through the space, means for supplying fuel and combustion supporting air to the lower intake end of said space, means positioned beyond the discharge end of said combustion space for abstracting heat from the hot gases discharged from said chamber, and-said combustion space betweensaid lower fuel intake end and the heat abstracting means being entirely closed thereby to prevent the introduction into the combustion space of any fluid except that introduced at said lower fuel intake end.

Signed at New York, in the county of New York and State of New York, this 18th day of June, A. D. 1925.

CHARLES D. MONTAGUE. 

